The Art Of Openworking And The Moser Streamliner Flying Tourbillon Skeleton
Less is more.
Moser’s identity over the years since the modern brand was launched in 2005, has gradually converged on something of stylistic tightrope act. A company with significant technical capabilities, Moser has also committed itself to clean, minimalist, even radically reductive designs across many of its models, especially in the Endeavour and Streamliner collections – the Endeavour Chinese Calendar is one of the most elegantly simplified examples of the complication ever made, and Moser has even experimented with reducing the visibility of, or even eliminating, its ornate cursive logo on the dials of some of its watches. (The Agengraphe chronograph caliber is one of the most complex and sophisticated chronographs in the world and Moser I think wisely, packages it in a lean, clean case from the Streamliner collection).
Moser has done openworked versions of one of its tourbillons in the past – following on its collaboration with M&F, the H. Moser x MB&F Endeavour Perpetual Tourbillon, Moser produced the Moser Pioneer Cylindrical Tourbillon Skeleton in 2022 – a model notable for its depth, as well as the transparency of the movement which is thanks to the removal of a considerable amount of metal from the baseplate.
The Moser Streamliner Flying Tourbillon is a bit of a different animal technically – instead of the single cylindrical balance spring in the MB&F collab and the Pioneer Cylindrical Tourbillon Skeleton, which is a rare example of a cylindrical balance spring in a modern watch. The cylindrical balance spring was invented by John Arnold for use in marine chronometers. The Streamliner Flying Tourbillon Skeleton on the other hand, uses the Moser double balance spring.
This is not the first time that a sports watch design has been combined with an openworked movement, but it’s a difficult thing to do convincingly since, at least from a classical perspective, those are two diametrically opposed idioms. Openworked watches were originally made by taking an existing caliber and using a piercing file and saw to remove metal from the interior of the plates, bridges, and usually, from the mainspring barrel cover as well. The trick is to remove as much metal as possible without compromising the structural integrity of the movement too severely and since such watches generally were more delicate than a non openworked watch, they were invariably intended as dressy curios rather than robust daily wear items.
Nowadays, however, openworking has become a much more diverse range of watchmaking. Today openworking can be done with much less risk, using spark erosion machines although the same problem of making sure that the movement remains reasonably strong and rigid still remains. Openworked movements may now also be designed as openworked calibers from the ground up; some of the Cartier Santos Dumont openworked models are excellent examples. And as Audemars Piguet has able demonstrated, combining an openworked movement with sports watch design can absolutely work, and work well, provided it’s the right sports watch design and the movement architecture complements the case.
The Moser Streamliner case is both very modern and slightly archaic – the case is deceptively simple at first glance but the construction is complex, with a curved profile accented by a radiating brushed finish on the bezel, and complemented by a bracelet whose curves echo the shape of the edges of the case itself. It’s one of the most successful integrated bracelet sports watch designs ever made, and a rare example of the integrated bracelet sports watch genre that looks really original (you will look in vain, for instance, for me-too bezel screws). The problem for Moser in designing an openworked tourbillon watch in a Streamliiner case, was how to make a movement whose architecture wouldn’t make it look like a charmingly underpowered mid-century four cylinder car engine dropped into a Bugatti Pur Sang.
For the Streamliner Tourbillon Flying Tourbillon, Moser began with an existing automatic tourbillon movement, HMC 804. The movement’s plates and bridges were completely redesigned and the goal was to produce something that was as transparent as possible, while still complementing the idiosyncratic Streamliner design. The problem of designing an openworked caliber is easier for a round case, which is a more or less neutral frame for a skeletonized movement; for a case that already has its own design identity the problem is harder but also more interesting.
Start with the curved and extremely thin bridge that loops around the tourbillon carriage and follow it from 5:00 clockwise. The bridge forms an arc framing the tourbillon and is punctuated by two train jewels before returning to the outer circumference of a very reduced dial that’s really no more than a narrow flange forming another arc around the movement as a whole, and which begins to narrow at the 2:00 marker before tapering off almost completely right where the bridge arcing over the tourbillon begins. (The flange supports the hour markers as well). This double arc design is graceful and also slightly asymmetrical and gives the watch a subtle dynamism – pure symmetry is all well and good but since movement train layouts are almost never completely symmetrical anyway, and while there’s a place for symmetry as a design goal, it can easily lead to a rather static and uninteresting visual experience.
The whole movement is full of similarly subtle pieces of ingenuity. There are two additional bridges shaped like very elongated S curves running from the center of the dial up to the 11:00 and 1:00 hour markers, and across the horizontal axis, a series of graceful arches and circles which visually tie the two lateral halves of the dial together and perform the difficult task of integrating the keyless works and crown into the rest of the design (a tough thing to do well; if you look at a lot of other openworked movements you’ll see that the keyless works often don’t seem a good fit. Here the clutch system has been designed so that its elongated arches harmonize visually with the rest of the movement).
And, rather miraculously, legibility is excellent, thanks to a savvy use of colors which contrast enough in tone and warmth to be instantly readable, while at the same time being close enough in saturation and brightness to feel like an integral part of the design. I’ve spent a lot of time reminding people that you cannot expect good legibility from an openworked watch and I still stand by that – openworking in general is antithetical to legibility – but darned if Moser hasn’t given us an example of having your cake and eating it too.
The Moser double balance spring was originally introduced back in 2010 (it’s made by Moser’s technical house, Precision Engineering AG) and it has the same basic purpose as a tourbillon, albeit it attacks the problem from a different angle. The tourbillon was originally designed by Breguet to address the problem of varying rates in different positions due to the effects of gravity, and produces a single average rate for all the vertical positions. The two balance springs are designed around the same concept as the Breguet overcoil, which is intended to keep the balance pivots centered by eliminating the thrusting action against their bearings which is caused by the asymmetrical development of a standard, single, flat balance spring. As you can see, the two balance springs, which are pinned at the collet and and at their studs 180º apart, will tend to also cancel those effects and combined with the tourbillon, produce theoretically better precision.
The real interest here though, is the obviously considerable thought and care that went from turning the caliber HMC 804 into the openworked caliber HMC 814. The graceful architecture of the movement along with harmonious curves of the case and braclet, make this an exceptionally harmonious (and unusually legible) example of an openworked movement watch.
The Moser Streamliner Tourbillon Skeleton: Case, steel, 40.0mm x 10.3mm (12.1mm with domed sapphire crystal) with sapphire crystal caseback; water resistance 12 atmospheres/120M. Dial, fully skeletonized, 5N gold plated faceted indexes; 5n gold plated hour and minute hands with Globolight inserts. Movement, openworked caliber HMC 814, automatic one minute flying tourbillon with double balance springs, running in 28 jewels at 21,600 vph. Anthracite finish, diamond-bevelling; gold skeletonized oscillating weight. Integrated steel bracelet with folding clasp. Price, CHF 79,000; for more info visit H-Moser.com.